The present invention relates to a training apparatus for the practice of puncturing blood vessels, said apparatus comprising a model arm and an air-tight, liquid-tight compressible liquid container and means for transferring liquid between the container and the model arm, which model arm comprises a core of a solid material, a tight-fitting cover of a penetrable material and at least one penetrable tube provided between the core and the cover, one end of the tube being connected to the liquid container and the other end being sealed.
Training apparatus of the above-mentioned type are used for the practice of performing injections, blood samplings, infusions, etc., the tubes of the model arm being used for simulating human blood vessels and the cover being used for simulating skin tissue.
A prior art training apparatus of the type mentioned above comprises a rigid liquid container for placing at a level above the model arm and which communicates with the ambient atmosphere, which container at its lower end includes an outlet to which a plastic tube forming a liquid connection with the tubes of the model arm is connected.
Prior to use the liquid container is filled with liquid and the tubes of the model arm are filled with liquid by evacuating the tubes of air, thereby causing the tubes to be filled with liquid by means of gravitational force. The liquid container is placed at such a distance above the model arm that a suitable pressure is provided in the tubes to simulate the protrusion of veins, which is necessary to allow insertion of a syringe and which in real life is established by constriction of the upper arm to prevent return flow from the veins of the arm.
In the prior art training apparatus the liquid container functions as a reservoir which is capable of both discharging and absorbing liquid. When liquid is discharged from the tubes, liquid will flow from the liquid container and into the tubes, thereby ensuring that the tubes are always filled. Vice versa, the liquid container will be able to absorb liquid in connection with, e.g., infusion provided the infusion pressure exceeds the pressure in the tubes.
In another prior art training apparatus a closable, collapsible liquid container is used instead of the rigid open liquid container.